Snake River (South Fork)
The best month to fish the Snake River (South Fork) is January. The month to avoid is May. Right now, in September, it is worth going.
- January: 71 out of 100
- February: 71 out of 100
- March: 71 out of 100
- April: 71 out of 100
- May: 35 out of 100
- June: 71 out of 100
- July: 55 out of 100
- August: 48 out of 100
- September: 71 out of 100
- October: 44 out of 100
- November: 71 out of 100
- December: 71 out of 100
This gauge does not report water temperature, so the check that would rule out water too warm to fight a fish in cannot run for this month. Treat the score as flow and season only, and ask a local shop about temperature before you travel in warm weather.
GAUGE 13171620 · COLOURED BY SEPTEMBER
Month by month
| MONTH | TYPICAL FLOW | RANGE (P20–P80) | WATER | AIR HIGH | RAIN | SCORE |
|---|---|---|---|---|---|---|
| January | 6,750 cfs | 6,546–9,010 | — | — | — | 71 |
| February | 6,951 cfs | 6,639–8,639 | — | — | — | 71 |
| March | 7,006 cfs | 6,278–10,260 | — | — | — | 71 |
| April | 6,938 cfs | 6,038–17,730 | — | — | — | 71 |
| May | 8,474 cfs | 6,379–12,930 | — | — | — | 35 |
| June | 7,023 cfs | 6,267–10,830 | — | — | — | 71 |
| July | 6,413 cfs | 5,508–8,487 | — | — | — | 55 |
| August | 5,859 cfs | 5,341–6,776 | — | — | — | 48 |
| SeptemberNOW | 6,621 cfs | 6,348–7,004 | — | — | — | 71 |
| October | 7,250 cfs | 6,978–7,768 | — | — | — | 44 |
| November | 7,104 cfs | 6,691–7,326 | — | — | — | 71 |
| December | 6,932 cfs | 6,657–7,300 | — | — | — | 71 |
WHERE THESE NUMBERS COME FROM
Flow and water temperature are medians of the monthly means reported by USGS gauge 13171620 over 2005-2024. Air temperature and precipitation are ten-year normals from Open-Meteo at this river’s gauge coordinates.
The window is deliberate. USGS’s own full-record statistics for a dammed river reach back before the dam — at Lees Ferry, to 1922, forty-one years before Glen Canyon closed — and describe a river that no longer exists.
Flow is scored against this river’s own fishable band of 6,750–7,023 cfs. There is no universal band: 8,000 cfs is low water on a big tailwater and a flood on a spring creek.
Water temperature is a ceiling rather than a weight. Above about 68°F a trout that is fought and released frequently dies anyway, so no month above that line is scored as worth booking, however good its flow.
The Snake River (South Fork) is at its best in January, flows near 6,750 cfs.
← RIVERS GOING WELL IN SEPTEMBERRegulations, licences and access change without notice and are not reproduced here as fact — check the state agency before you travel. A median describes twenty years; it does not forecast your week. Source: U.S. Geological Survey, National Water Information System.